[pwjone1]

As an Electrical Engineer, I think I partly understand the request to turn off all electrical devices. You can have electromagnetic interference (EMI) from any electronic device. It doesn't have to be designed to transmit or receive, it's going to happen, so long as it's on. It's generally a function of the cycle times and so forth, for a digital device, but there can effectively be harmonics, tends to leak where the cases are not quite designed right, or there's an external connection point, etc. The airplanes electronics or sensors could be sensitive, depending on the frequencies involved. They should be normally designed to be a little tolerant, people forget to turn things off. But new devices come along all of the time, so.... Plus, it's probably just simplest to tell people to turn them off, rather then spend time arguing about whether device x is OK on plane y. Probably overly cautious in terms of a well designed electronic device, FCC OK'd, etc., and I would expect that the laws will change within the next 10 years, but I suppose the FAA is just being cautious.

On a flight back from Zurich, there was a beep as I went through the entry door to the airplane, asked and was told it was a phone detector. Rather new Boeing, so that was an interesting development. Ironically, my phone was powered down at the time (Europe, CDMA is pretty useless), but my Kindle 2 e-Reader was not, had just been reading it in the lounge, closed it to get on the plane (although I thought I had wireless off). I'm not sure why the door detector, they don't usually make you turn the phone off until the door is closed and they're pulling away, but maybe they're getting ready to have you power the phone off on entrance to the plane. There were a couple of new security measures in place for this flight, they really played 20 questions about my laptop (which was new, somehow they don't seem to like newer laptops) and various other bits and pieces of electronic devices, anything with a battery.